Triple-play technology allows offering services that require very high performance in terms of bit-rate and stability. When wireline infrastructure is used for data transmission, as is the case in xDSL-based access networks, attaining the required level of performance can become challenging, especially for longer loops. Moreover, in the presence of physical defects, the quality of service decreases drastically, and the quality of experience of the end user may become unacceptably low. In the case of IP TV, such a low quality of experience may present itself in the form of errors such as artifacts in the image and temporary freezing of the video stream. Hence, it is desirable for the network operator to have a way to adequately detect topological aspects and physical defects of the network, in order to be able to perform the necessary optimizations and/or maintenance interventions in a timely manner.